In the discussion that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicants expressly reserve the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention.
There are several conventional cutting tools for both trim and rout operations of materials, including for CFRP materials. However, these conventional cutting tools have weaknesses in the noted operations.
One type of conventional cutting tool is a helical endmill. Helical endmills consist of either right hand (RH) or left hand (LH) cutting edges, can be used for roughing or finishing, and typically produces a good finish. However, the cutting edges are only in one direction and can negatively impact the cutting operation by, for example, delamination of the part.
Another type of conventional cutting tool is a serration router. Serration routers contain either RH or LH cutting edges with opposing serrations similar to a roughing endmill. However, serration routers can produce delamination one side.
Another type of conventional cutting tool is a helical burr, which consists of shallow RH and LH flutes that create small pyramid type cutting edges. However, helical burrs produce varying results depending on the makeup and direction of fibers in the CFRP workpiece.
A further type of conventional cutting tool is a compression endmill with, in separate areas along the length of the cutter, RH cutting edges and LH cutting edges, which together produce compression in the workpiece to reduce delamination. However, the limited cutting zone reduces the versatility and usefulness of this tool.
Aspects of conventional cutting tool are disclosed in FR 2 972 122, U.S. Pat. No. 7,090,442 and U.S. Patent Publication Nos. 2013/0209184 and 2015/0093204.